Del Fresno Carmen, Cesca Simone, Klügel Andreas, Domínguez Cerdeña Itahiza, Díaz-Suárez Eduardo A, Dahm Torsten, García-Cañada Laura, Meletlidis Stavros, Milkereit Claus, Valenzuela-Malebrán Carla, López-Díaz Rubén, López Carmen
Instituto Geográfico Nacional (IGN), Madrid, Spain.
GFZ German Research Centre for Geosciences, Potsdam, Germany.
Nat Commun. 2023 Jan 23;14(1):358. doi: 10.1038/s41467-023-35953-y.
The 2021 volcanic eruption at La Palma, Canary Islands, was the island's most voluminous historical eruption. Little is known about this volcano's feeding system. During the eruption, seismicity was distributed in two clusters at ~10-14 km and ~33-39 km depth, separated by an aseismic zone. This gap coincides with the location of weak seismic swarms in 2017-2021 and where petrological data have implied pre-eruptive magma storage. Here we use seismological methods to understand the seismic response to magma transfer, with 8,488 hypocentral relocations resolving small-scale seismogenic structures, and 156 moment tensors identifying stress heterogeneities and principal axes flips. Results suggest a long-lasting preparatory stage with the progressive destabilisation of an intermediate, mushy reservoir, and a co-eruptive stage with seismicity controlled by the drainage and interplay of two localised reservoirs. Our study provides new insights into the plumbing system that will improve the monitoring of future eruptions in the island.
2021年加那利群岛拉帕尔马岛的火山喷发是该岛历史上规模最大的一次喷发。人们对这座火山的补给系统知之甚少。在喷发期间，地震活动分布在深度约10 - 14千米和33 - 39千米的两个区域，中间被一个无震带隔开。这个间隔与2017 - 2021年弱地震群的位置以及岩石学数据所暗示的喷发前岩浆储存位置相吻合。在此，我们运用地震学方法来了解对岩浆运移的地震响应，通过8488次震源重定位解析小尺度地震成因结构，并利用156个矩张量识别应力非均匀性和主轴翻转。结果表明存在一个长期的准备阶段，其间一个中间的、糊状储层逐渐失稳，以及一个同喷发阶段，此阶段的地震活动受两个局部储层的排水作用和相互作用控制。我们的研究为该管道系统提供了新的见解，这将有助于改进对该岛未来火山喷发的监测。
